Epithelial-mesenchymal interactions in gut morphogenesis

描述(申请人提供)：上皮-间充质的相互作用对正常的形态发生至关重要 以及隐窝-绒毛轴的维护。调节这些的分子 互惠互动直到最近才开始被描述。我们有 发现一种间充质蛋白，表吗啡，作为一种假定的调节因子 上皮形态发生。我们发现，这种分子对 肠上皮的形态发生和分化。然而， 表吗啡发挥作用的机制尚不清楚，体内 抑制表吗啡在整个动物体内表达的效果尚未得到证实 描述。我们对这一应用的假设是，表吗啡的作用是 至少部分是通过调节可溶性物质的分泌来实现的 它们在形态发生中很重要。根据我们的初步数据，其中一个 候选人可能是Sonic Hedgehog(Shh)，一个关键的调节器 早期肠道个体发育中的肠道-内胚层-间充质信号。我们证明了 通过抗体注射阻断刺猬信号通路产生深远的影响 出生后肠道形态改变，绒毛排列紊乱，奔跑和早期 死亡。这些效应在体外用上皮肌成纤维细胞重现。 本实验室建立的共培养模型。当前的主要假设是 建议如下：1.肠道肌成纤维细胞产生表吗啡，它调节 隐窝绒毛轴的形成和维持。2.刺猬信号 通路是维持出生后隐窝-绒毛轴所必需的。 具体目的是：1.确定表吗啡的诱导机制 隐窝绒毛的形态发生和细胞分化。2.体内检测 表吗啡通过建立表吗啡-/-小鼠发挥作用。3.确定是否 刺猬对出生后上皮形态发生和发育的影响 分化是通过上皮-间充质相互作用介导的，使用 上皮-肌成纤维细胞共培养体系。这件事的意义 应用程序是基于我们最近识别的 间充质/肌成纤维细胞基因在调控中的重要作用 隐窝绒毛轴的形态发生。刺猬信号在出生后的作用 肠道个体发育也已建立，并将进行进一步研究。特定的 对于这个RFA的研究范围，这些研究将表征 上皮-间充质之间的相互作用是正常发育的基础。我们还将 建立一种新的模型--表吗啡缺失小鼠 调控间充质细胞群的分子特性 发育中和成人胃肠道上皮细胞的更新。

DESCRIPTION (Provided by Applicant): Epithelial-mesenchymal interactions are critical for the normal morphogenesis and maintenance of the crypt-villus axis. The molecules that regulate these reciprocal interactions have only recently begun to be described. We have identified a mesenchymal protein, epimorphin, as a putative regulator of epithelial morphogenesis. We show that this molecule has profound effects on morphogenesis and differentiation of the intestinal epithelium. However, the mechanism by which epimorphin exerts its effects is unknown, and the in vivo effects of inhibiting epimorphin expression in whole animals have not yet been described. Our hypothesis for this application is that epimorphin's effects are mediated, at least in part, by regulating the secretion o soluble substances that are important in morphogenesis. Based on our preliminary data, one such candidate may be sonic hedgehog (Shh)a critical regulator of gut-endodermal-mesenchymal signaling in early gut ontogeny. We show that blocking hedgehog signaling pathways by antibody infusion produces profound changes in postnatal gut morphology, with disorganized villi, runting and early death. These effects are recapitulated in vitro in an epithelial-myofibroblast co-culture model developed in our lab. The major hypotheses of the current proposal are: 1. Intestinal myofibroblasts produce epimorphin which regulates the formation and maintenance of the crypt-villus axis. 2. Hedgehog signaling pathways are required for the maintenance of the postnatal crypt-villus axis. The Specific Aims are: 1. Determine the mechanisms by which epimorphin induces crypt-villus morphogenesis and cytodifferentiation. 2. Determine the in vivo function of epimorphin by creating epimorphin -/- mice. 3. Determine whether the effects of hedgehog on postnatal epithelial morphogenesis and differentiation are mediated via epithelial-mesenchymal interactions, using an epithelial-myofibroblast co-culture system. The significance of this application is based on our recent identification of a mesenchymal/myofibroblast gene that plays an important role in the regulation of crypt-villus axis morphogenesis. A role for hedgehog signaling in postnatal gut ontogeny has also been established and will be further examined. Specific to the research scope for this RFA, these studies will characterize epithelial-mesenchymal cross talk underlying normal development. We will also establish a novel model, the epimorphin null mouse, for characterizing the molecular properties of the mesenchymal cell populations that regulate epithelial cell renewal in the developing and adult GI tract.